drivers/rtc/rtc-armada38x.c

   1 /*
   2  * RTC driver for the Armada 38x Marvell SoCs
   3  *
   4  * Copyright (C) 2015 Marvell
   5  *
   6  * Gregory Clement <gregory.clement@free-electrons.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of the
  11  * License, or (at your option) any later version.
  12  *
  13  */
  14
  15 #include <linux/delay.h>
  16 #include <linux/io.h>
  17 #include <linux/module.h>
  18 #include <linux/of.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/rtc.h>
  21
  22 #define RTC_STATUS          0x0
  23 #define RTC_STATUS_ALARM1           BIT(0)
  24 #define RTC_STATUS_ALARM2           BIT(1)
  25 #define RTC_IRQ1_CONF       0x4
  26 #define RTC_IRQ1_AL_EN              BIT(0)
  27 #define RTC_IRQ1_FREQ_EN            BIT(1)
  28 #define RTC_IRQ1_FREQ_1HZ           BIT(2)
  29 #define RTC_TIME            0xC
  30 #define RTC_ALARM1          0x10
  31
  32 #define SOC_RTC_INTERRUPT   0x8
  33 #define SOC_RTC_ALARM1          BIT(0)
  34 #define SOC_RTC_ALARM2          BIT(1)
  35 #define SOC_RTC_ALARM1_MASK     BIT(2)
  36 #define SOC_RTC_ALARM2_MASK     BIT(3)
  37
  38 struct armada38x_rtc {
  39         struct rtc_device   *rtc_dev;
  40         void __iomem        *regs;
  41         void __iomem        *regs_soc;
  42         spinlock_t          lock;
  43         /*
  44          * While setting the time, the RTC TIME register should not be
  45          * accessed. Setting the RTC time involves sleeping during
  46          * 100ms, so a mutex instead of a spinlock is used to protect
  47          * it
  48          */
  49         struct mutex        mutex_time;
  50         int                 irq;
  51 };
  52
  53 /*
  54  * According to the datasheet, the OS should wait 5us after every
  55  * register write to the RTC hard macro so that the required update
  56  * can occur without holding off the system bus
  57  */
  58 static void rtc_delayed_write(u32 val, struct armada38x_rtc *rtc, int offset)
  59 {
  60         writel(val, rtc->regs + offset);
  61         udelay(5);
  62 }
  63
  64 static int armada38x_rtc_read_time(struct device *dev, struct rtc_time *tm)
  65 {
  66         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
  67         unsigned long time, time_check;
  68
  69         mutex_lock(&rtc->mutex_time);
  70         time = readl(rtc->regs + RTC_TIME);
  71         /*
  72          * WA for failing time set attempts. As stated in HW ERRATA if
  73          * more than one second between two time reads is detected
  74          * then read once again.
  75          */
  76         time_check = readl(rtc->regs + RTC_TIME);
  77         if ((time_check - time) > 1)
  78                 time_check = readl(rtc->regs + RTC_TIME);
  79
  80         mutex_unlock(&rtc->mutex_time);
  81
  82         rtc_time_to_tm(time_check, tm);
  83
  84         return 0;
  85 }
  86
  87 static int armada38x_rtc_set_time(struct device *dev, struct rtc_time *tm)
  88 {
  89         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
  90         int ret = 0;
  91         unsigned long time, flags;
  92
  93         ret = rtc_tm_to_time(tm, &time);
  94
  95         if (ret)
  96                 goto out;
  97         /*
  98          * Setting the RTC time not always succeeds. According to the
  99          * errata we need to first write on the status register and
 100          * then wait for 100ms before writing to the time register to be
 101          * sure that the data will be taken into account.
 102          */
 103         mutex_lock(&rtc->mutex_time);
 104         rtc_delayed_write(0, rtc, RTC_STATUS);
 105         msleep(100);
 106         rtc_delayed_write(time, rtc, RTC_TIME);
 107         mutex_unlock(&rtc->mutex_time);
 108
 109 out:
 110         return ret;
 111 }
 112
 113 static int armada38x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 114 {
 115         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 116         unsigned long time, flags;
 117         u32 val;
 118
 119         spin_lock_irqsave(&rtc->lock, flags);
 120
 121         time = readl(rtc->regs + RTC_ALARM1);
 122         val = readl(rtc->regs + RTC_IRQ1_CONF) & RTC_IRQ1_AL_EN;
 123
 124         spin_unlock_irqrestore(&rtc->lock, flags);
 125
 126         alrm->enabled = val ? 1 : 0;
 127         rtc_time_to_tm(time,  &alrm->time);
 128
 129         return 0;
 130 }
 131
 132 static int armada38x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 133 {
 134         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 135         unsigned long time, flags;
 136         int ret = 0;
 137         u32 val;
 138
 139         ret = rtc_tm_to_time(&alrm->time, &time);
 140
 141         if (ret)
 142                 goto out;
 143
 144         spin_lock_irqsave(&rtc->lock, flags);
 145
 146         rtc_delayed_write(time, rtc, RTC_ALARM1);
 147
 148         if (alrm->enabled) {
 149                         rtc_delayed_write(RTC_IRQ1_AL_EN, rtc, RTC_IRQ1_CONF);
 150                         val = readl(rtc->regs_soc + SOC_RTC_INTERRUPT);
 151                         writel(val | SOC_RTC_ALARM1_MASK,
 152                                rtc->regs_soc + SOC_RTC_INTERRUPT);
 153         }
 154
 155         spin_unlock_irqrestore(&rtc->lock, flags);
 156
 157 out:
 158         return ret;
 159 }
 160
 161 static int armada38x_rtc_alarm_irq_enable(struct device *dev,
 162                                          unsigned int enabled)
 163 {
 164         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 165         unsigned long flags;
 166
 167         spin_lock_irqsave(&rtc->lock, flags);
 168
 169         if (enabled)
 170                 rtc_delayed_write(RTC_IRQ1_AL_EN, rtc, RTC_IRQ1_CONF);
 171         else
 172                 rtc_delayed_write(0, rtc, RTC_IRQ1_CONF);
 173
 174         spin_unlock_irqrestore(&rtc->lock, flags);
 175
 176         return 0;
 177 }
 178
 179 static irqreturn_t armada38x_rtc_alarm_irq(int irq, void *data)
 180 {
 181         struct armada38x_rtc *rtc = data;
 182         u32 val;
 183         int event = RTC_IRQF | RTC_AF;
 184
 185         dev_dbg(&rtc->rtc_dev->dev, "%s:irq(%d)\n", __func__, irq);
 186
 187         spin_lock(&rtc->lock);
 188
 189         val = readl(rtc->regs_soc + SOC_RTC_INTERRUPT);
 190
 191         writel(val & ~SOC_RTC_ALARM1, rtc->regs_soc + SOC_RTC_INTERRUPT);
 192         val = readl(rtc->regs + RTC_IRQ1_CONF);
 193         /* disable all the interrupts for alarm 1 */
 194         rtc_delayed_write(0, rtc, RTC_IRQ1_CONF);
 195         /* Ack the event */
 196         rtc_delayed_write(RTC_STATUS_ALARM1, rtc, RTC_STATUS);
 197
 198         spin_unlock(&rtc->lock);
 199
 200         if (val & RTC_IRQ1_FREQ_EN) {
 201                 if (val & RTC_IRQ1_FREQ_1HZ)
 202                         event |= RTC_UF;
 203                 else
 204                         event |= RTC_PF;
 205         }
 206
 207         rtc_update_irq(rtc->rtc_dev, 1, event);
 208
 209         return IRQ_HANDLED;
 210 }
 211
 212 static struct rtc_class_ops armada38x_rtc_ops = {
 213         .read_time = armada38x_rtc_read_time,
 214         .set_time = armada38x_rtc_set_time,
 215         .read_alarm = armada38x_rtc_read_alarm,
 216         .set_alarm = armada38x_rtc_set_alarm,
 217         .alarm_irq_enable = armada38x_rtc_alarm_irq_enable,
 218 };
 219
 220 static __init int armada38x_rtc_probe(struct platform_device *pdev)
 221 {
 222         struct resource *res;
 223         struct armada38x_rtc *rtc;
 224         int ret;
 225
 226         rtc = devm_kzalloc(&pdev->dev, sizeof(struct armada38x_rtc),
 227                             GFP_KERNEL);
 228         if (!rtc)
 229                 return -ENOMEM;
 230
 231         spin_lock_init(&rtc->lock);
 232         mutex_init(&rtc->mutex_time);
 233
 234         res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc");
 235         rtc->regs = devm_ioremap_resource(&pdev->dev, res);
 236         if (IS_ERR(rtc->regs))
 237                 return PTR_ERR(rtc->regs);
 238         res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc-soc");
 239         rtc->regs_soc = devm_ioremap_resource(&pdev->dev, res);
 240         if (IS_ERR(rtc->regs_soc))
 241                 return PTR_ERR(rtc->regs_soc);
 242
 243         rtc->irq = platform_get_irq(pdev, 0);
 244
 245         if (rtc->irq < 0) {
 246                 dev_err(&pdev->dev, "no irq\n");
 247                 return rtc->irq;
 248         }
 249         if (devm_request_irq(&pdev->dev, rtc->irq, armada38x_rtc_alarm_irq,
 250                                 0, pdev->name, rtc) < 0) {
 251                 dev_warn(&pdev->dev, "Interrupt not available.\n");
 252                 rtc->irq = -1;
 253                 /*
 254                  * If there is no interrupt available then we can't
 255                  * use the alarm
 256                  */
 257                 armada38x_rtc_ops.set_alarm = NULL;
 258                 armada38x_rtc_ops.alarm_irq_enable = NULL;
 259         }
 260         platform_set_drvdata(pdev, rtc);
 261         if (rtc->irq != -1)
 262                 device_init_wakeup(&pdev->dev, 1);
 263
 264         rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name,
 265                                         &armada38x_rtc_ops, THIS_MODULE);
 266         if (IS_ERR(rtc->rtc_dev)) {
 267                 ret = PTR_ERR(rtc->rtc_dev);
 268                 dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
 269                 return ret;
 270         }
 271         return 0;
 272 }
 273
 274 #ifdef CONFIG_PM_SLEEP
 275 static int armada38x_rtc_suspend(struct device *dev)
 276 {
 277         if (device_may_wakeup(dev)) {
 278                 struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 279
 280                 return enable_irq_wake(rtc->irq);
 281         }
 282
 283         return 0;
 284 }
 285
 286 static int armada38x_rtc_resume(struct device *dev)
 287 {
 288         if (device_may_wakeup(dev)) {
 289                 struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 290
 291                 return disable_irq_wake(rtc->irq);
 292         }
 293
 294         return 0;
 295 }
 296 #endif
 297
 298 static SIMPLE_DEV_PM_OPS(armada38x_rtc_pm_ops,
 299                          armada38x_rtc_suspend, armada38x_rtc_resume);
 300
 301 #ifdef CONFIG_OF
 302 static const struct of_device_id armada38x_rtc_of_match_table[] = {
 303         { .compatible = "marvell,armada-380-rtc", },
 304         {}
 305 };
 306 #endif
 307
 308 static struct platform_driver armada38x_rtc_driver = {
 309         .driver         = {
 310                 .name   = "armada38x-rtc",
 311                 .pm     = &armada38x_rtc_pm_ops,
 312                 .of_match_table = of_match_ptr(armada38x_rtc_of_match_table),
 313         },
 314 };
 315
 316 module_platform_driver_probe(armada38x_rtc_driver, armada38x_rtc_probe);
 317
 318 MODULE_DESCRIPTION("Marvell Armada 38x RTC driver");
 319 MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@free-electrons.com>");
 320 MODULE_LICENSE("GPL");